High speed hydraulic pump

ABSTRACT

THIS DISCLOSURE RELATES TO A HIGH SPEED, HIGH EFFICIENCY HYDRAULIC PUMP MADE FROM A PLURALITY OF PLATE-LIKE MEMBERS. A PUMP CAVITY FOR A PAIR OF INTERMESHING GEAR MEMBERS IS FORMED IN ONE OF THE PLATES. INLET AND OUTLET CONDUITS ARE PROVIDED TO EITHER SIDE OF THE PUMP CAVITY. A RECYCLE BYPASS LINE CONTAINING A PRESSURE CONTROLLED VALVE IS PROVIDED TO RECYCLE FLUID AT THE OUTLET SIDE OF THE PUMP TO THE INLET SIDE IN THE EVENT THAT BACK PRESSURE AT THE OUTLET EXCEEDS THAT OF THE INLET BY A PREDETERMINED AMOUNT. ALIGNING PINS EXTEND INTO OR THROUGH ALL OF THE PLATES TO ENSURE PRECISE ALIGNMENT OF THE PUMP PARTS THEREBY PERMITTING SMALLER TOLERANCES TO BE USED IN THE PUMP CAVITY. O-RING SEALS ARE PROVIDED BETWEEN EACH OF THE PLATES TO AVOID EXTERNAL LEAKAGE OUTSIDE THE CAVITY.

United States Patent Ofiice 3,554,678 Patented Jan. 12, 1971 3,554,678HIGH SPEED HYDRAULIC PUMP Edward J. Jackoboice and Gerrit H. Kruizenga,Grand Rapids, Mich., assignors' to Monarch Road Machinery Company, GrandRapids, Mich., a corporation of Michigan Filed Oct. 16, 1968, Ser. No.780,925

Int. Cl. F04c 1/08 US. Cl. 418-206 9 Claims ABSTRACT OF THE DISCLOSUREThis disclosure relates to a high speed, high efiiciency hydraulic pumpmade from a plurality of plate-like members. A pump cavity for a pair ofintermeshing gear members is formed in one of the plates. Inlet andoutlet conduits are provided to either side of the pump cavity. Arecycle bypass line containing a pressure controlled valve is providedto recycle fluid at the outlet side of the pump to the inlet side in theevent that back pressure at the outlet exceeds that of the inlet by apredetermined amount. Aligningfpins extend into or through all of theplates to ensure precise alignment of the pump parts thereby permittingsmaller tolerances to be used in the pump cavity. O-ring seals areprovided between each of the plates to avoid external leakage outsidethe cavity.

This invention relates to a high speed, high efliciency hydraulic. pump.

High speed hydraulic pumps heretofore developed reach a maximumoperating speed of about 3,300 r.p.m. After that, the efficiency dropsdown and the pumps begin to become excessively overheated. Further, inorder to operate most pumps efficiently, special and expensive hydraulicfluid is required.

It is an object of this invention to provide a high speed, high volume,and highly efiicient hydraulic pump.

It is a further object of this inventionto provide a high speed pumpwhich operates efficiently with motor oil, transmission oil, and doesnot require expensive hydraulic fluid.

It is a further object of this invention to provide a pump which canoperate at speeds in excess of 5,000 r.p.m. without excessive heatbuildup.

Other aspects, objects, and the several advantages of this invention areapparent to one skilled in the art from a study of this disclosure, thedrawings, and the appended claims.

According to the invention, there is provided a high speed, high volumehydraulic pump formed from a plurality of plate members including a basemember, a cylinder plate member and a suction plate member. The cylinderplate is fixed between the base member and the suction plate member. Apump cavity is formed in the cylinder plate member and intermeshing gearmeans are provided within the pump cavity having close tolerancesbetween the walls of the pump cavity and the outer portions of the gearmeans. A drive shaft extends through the base and engages one of theintermeshing gear means. An inlet conduit means is provided in thesuction plate member, the inlet conduit communicating with the pumpcavity at an intake side of the point of the meshing of the gear means.An outlet conduit communicates with the pump cavity at an opposite sideof the meshing of the gear means so that liquid in the inlet conduitmeans will be pumped to the outlet conduit means as the gear meansrotate within the pump cavity.

According to one aspect of the invention, axial aligning pins areprovided in the base member and extend through the cylinder plate memberand into at least a portion of the suction member thereby ensuringprecise alignment of the base member and the suction plate member sothat close tolerances can be maintained between the walls of the pumpcavity and the outer portions of the gear means.

According to another aspect of this invention, a recycle conduit isprovided in the base member, the recycle conduit communicating at oneend with one side of the point of meshing of the gear means and at theother end with the opposite point of meshing of the gear means. Biasedcheck valve means are provided in the recycle conduit to permit fluid toflow from the discharge side to the intake side when the pressure at thedischarge side exceeds that of the intake side by a predetermined value.

In another aspect of the invention, O-rings are provided between eachplate in the pump to seal oh the pump chamber against leakage.

In still another aspect of this invention, a removable wear plate isprovided between the base and the cylinder plate member, the wear platehaving a bearing surface for the gear means. The Wear plate can bereplaced when the gear means wear down the surface of the wear plate.

In still another aspect of the invention, each gear means has eleventeeth which are frustro-conically shaped, the sides of each tooth beingbowed outwardly.

The invention will now be described with reference to the accompanyingdrawings in which:

FIG. 1 is a perspective view of a pump which embodies the invention;

FIG. 2 is an exploded view of the pump shown in FIG. 1;

FIG. 3 is a top view of the pump shown in FIGS. 1 and 2 with the topplate member removed and generally seen along lines IIIIII of FIG. 6;

FIG. 4 is a sectional view of the pump shown in FIGS. 1 through 3generally seen along lines IVIV of FIG. 6;

FIG. 5 is another sectional view of the pump shown in FIGS. 1 through 4generally seen along lines V-V of FIG. 6;

;FIG. 6 is a side sectional view of the pump shown in FIGS. 1 through 5as seen along lines VI-VI of FIG. 3; and

FIG. 7 is a sectional view taken along lines VIIVII of FIG. 3.

Referring now to the drawings, there is shown a high speed, high volumehydraulic pump. The pump has a power-driven shaft 12, a base 14, a wearor pressure plate 16, a cylinder plate 18 and a suction plate 20. Aninlet line 22 is provided for supplying fluid to the pump which pumpsthe fluid through an outlet line 24 under pressure.

The power-driven shaft 12 is journalled in the base 14 and the suctionplate 20. For this purpose, outer bearings 26 and inner bearings 28 havebeen provided in the base 14. Bearings 38 are provided in suction plate20 for rotatably supporting the power-driven shaft 12 in suction plate20. A washer seal 27 is provided between outer bearings 26 and innerbearings 28 to seal the pump chamber. The outer bearings 26 are providedto protect the seal 27 and to prevent the outer shaft from bending.

The shaft 12 has a longitudinal groove 32 and a pair of circumferentialgrooves 34 and 36. A first gear member 40 is secured to the power shaft12 through a keyway 44 positioned in the longitudinal groove 32 andthrough a pair of retainer rings 62 which are positioned on either sideof the first gear member 40 in the circumferential grooves 34 and 36.The keyway 44 locks in an axial groove in the inside surface of firstgear means.

The first gear member 40 intermeshes with a second gear member 42 whichis supported on an idler shaft 48 in a manner similar to that in whichthe first gear member 40 is fixed to the power-driven shaft 21. A keyway46 is positioned in longitudinal groove 54 of the idler shaft 48 and ispositioned in a longitudinal groove on the interior surface of thesecond gear member 42. Retainer rings 62 are positioned incircumferential grooves 50 and 52 of the idler shaft on either side ofthe second gear member 42 to fix the second gear member 42longitudinally on the idler shaft 48.

The idler shaft 48 is journalled in base 14 at one end and at suctionplate 20 at the other end. To this end, bearings 56 and 58 are providedin base 14 and bearings 60 are provided in suction plate 20.

The base 14 contains an axial bore 64 for the idler shaft 48 and for thebearings 56 and 58. A second axial bore 66 is provided for thepower-driven shaft 12 and the bearings 26, 28, and 30. A third axialbore 68 and a forth axial bore 70 are provided for a recycle bypassline. Bore 68 communicates with bore 70 through radial bore 72 and port74. The flow of fluid through the recycle line is blocked by ball 76seated against port 74 by the pressure of spring 78 which is held by athreaded retainer plug 80. Threads 82 are provided in the radial bore 72to threadably engage the retainer plug 80. By this device, the pressureon ball 76 can be adjusted. Therefore, the required differentialpressure required to permit flow between bore 68 and 70 is adjustable.

The wear plate 16 contains an annular groove 92 in the bottom face toposition an O-ring 86 for sealing the area between the base 14 and thewear plate 16.

The wear plate 16 has axial bores 88 and 90 for permitting passage ofpower-driven shaft 12 and idler shaft 48 respectively.

The base 14 contains aligning pins 96 and 98 on opposite sides, thealigning pins extending axially parallel to the power shaft 12. The basealso contains a plurality of circumferentially spaced threaded bores100. For simplicity, only two of such bores have been shown (FIG. 5).However, in practice, a plurality of such bores will be spaced about theperiphery of the base 12.

The wear plate contains peripheral axial bores 102 and 104 which arealigned with the aligning pins 96 and 98 respectively. Peripheral axialbores 105 are provided, which bores communicate with the threaded bores100 of base 12. Central axial bores 106 and 108 are also provided forcommunicating with bores 70 and 68 respectively. An indented slot 107 inthe top face of wear plate 16 communicates with axial bore 106. A secondindented slot 109 in the top face plate of wear plate 16 communicateswith axial bore 108.

An annular groove 94 is formed in the top face of the wear plate 16 forthe purpose of seating O-ring 112.

A central pump cavity 114 is axially bored in cylinder plate 18. Thepump cavity 114 conforms to the outer periphery of the rotating gearmembers 40 and 42 except at the points where the gear members intermesh.At that intermeshing point, an inlet lobe 114a is formed at one side ofthe point where the gears intermesh and an outlet lobe 114b is formed onthe opposite side of the pump cavity from the inlet lobe 114a and wherethe gears intermesh.

Axial bores 116 and 118 are provided at the periphery of the cylinderplate 18 for alignment with the aligning pins 96 and 98 respectively.Axial bores 120 are provided around the periphery of the cylinder plate118, which bores 120 communicate with the bores 105 and the threadedbores 100.

An annular groove 122 is provided in the top face of the cylinder plate118 for seating an O-ring 126 to seal the area between the top plate 20and the cylinder plate 18. To this end, a second annular groove 124 isprovided in the bottom face of the top plate 20. The O-ring 26 is alsoseated in this groove 124.

The suction plate 20 contains an axial bore 128 for receiving the top ofaligning pin 96 and an axial bore 130 for receiving the top of thealigning pin 98. Axial bores 132 are also provided in the top plate 18around the periphery thereof. The bores 132 communicate with the bores120 of the cylinder plate, with bores 105 of the wear plate 16, and withthreaded bores 100' of the base 12. Fastening bolts 142 extend throughbores 132, 120, 105 and threadably engage the threaded bores 100 of base12. In this manner, the base 14, the wear plate 16, the cylinder plate18 and the top plate 20 can be securely fastened together.

The suction plate 20 is also provided with an inlet bore 134, an outletbore 136, communicating with the inlet lobe 114a and the outlet lobe114b respectively. An axial bore 138 is provided for idler shaft 48 andbearing 60. Another axial bore is provided for the power shaft 12 andthe bearings 38.

OPERATION In operation, rotational power is supplied to shaft 12 causingrotation of the first and second gear members 40 and 42 in a directionillustrated by the arrows in FIG. 1 and FIG. 3. Any suitable fluid canbe supplied to inlet line 22. The fluid will pass through inlet bore 134and into the inlet lobe 114a. The rotation of the gear members 40 and 42will carry the fluid around the periphery of the central pump cavity 114between the teeth. As the fluid reaches the outlet lobe 1141), the fluidis pushed from between the teeth by the intermeshing of the gear members40 and 42. To this end, the indented slot 107 is provided to facilitatethe movement of the fluid from between the teeth as the gears intermeshand into the outlet lobe area 114b. As is illustrated in FIG. 3, theintermeshing of the teeth of the gear members 40 and 42 substantiallyfill the space between the teeth thereby forcing substantially all ofthe fluid into the outlet lobe 114b. As the pressure in the outlet lobebuilds up, the fluid will flow upwardly through the outlet bore 136 andinto the outlet line 24.

When there is a certain amount of back pressure in the outlet line 24,the pressure will build up in the outlet lobe 114b. This pressure willbe transmitted to the spring biased ball 76 in port 74 through bores 106and 68. When the pressure in the outlet lobe 114b exceeds that of theinlet lobe 114a by a predetermined amount, then the pressure will forcethe ball 76 away from the seat at port 74 thereby permitting flow offluid from the outlet lobe 114b to the inlet lobe 114a through bores106, 68, port 74, bores 72, 70 and 109. The pressure differentialrequired to cause recycle can be adjusted by adjusting the threadedretainer plug 80 within the bore 78. With the use of the aligning pin 96and 98, the central pump cavity 114 and the first and second gearmembers 40 and 42 can be machined to much closer tolerances. This meansthat the pump will operate much more efliciently, especially at highspeeds.

As illustrated in FIGS. 6 and 7, the thickness of the first and secondgear members is substantially the same as the thickness of the cylinderplate 18. The upper face of the wear plate 16 and the lower face of thesuction plate 20 therefore provides bearing surfaces for the bottom andtop respectively of the first and second gear members 40 and 42. Afterextensive use of the pump, the bearing surfaces can be machined or thewear plate 16 and/or the top plate 20 can be replaced without replacingthe entire pump.

The use of the O-ring seals between each of the plates maximizes thetightness of the pump cavity to thereby prevent external leakage of thefluid used in the pump.

In the preferred embodiment of the invention illustrated in the drawingsand heretofore described, each gear member 40 and 42 contains eleventeeth equally spaced about the periphery. Each tooth is generallyfrusto-conically shaped and spaced at the base from an adjacent tooth adistance substantially equal to the width of each tooth at the peak. Bythis construction, substantially complete removal of the fluid betweenthe gear teeth is effected. It has further been found that theelficiency and speed of operation can be improved by providing eachtooth with sides bowed outwardly toward adjacent teeth. Thisconstruction is seen more clearly in FIG. 3.

As an example of suitable gears, the following specifications are given:H.O.B. ll, 1 2D.P., 14 /2P.A., 1.211 plus .000 minus .001 over 0160pins.

SPECIFIC EXAMPLE A pump constructed according to the invention and asset forth in the preceding specification was tested according to thefollowing procedure: the pump was connected to a three inch by six inchdouble acting hydraulic cylinder having a 42.36 cubic inch displacement.Transmission oil type A at 80 F. was used in the system; The gear sizewas A inch. Various back pressures were set on the cylinder and the timeto completely displace the piston in the cylinder was measured. Thepower input was measured. The following is a tabulation of the resultsof th1s test:

TYPE FLUID: TRANSMISSION OIL TYPE A Displace Back per pressure VolumePercent Time second p.s.i.a. (gaL/min.) efiiciency (sec.) (cu. in.)

As can be seen from the above table, the pump 0perated at highefficiencies (up to 62.2%) at back pressures up to 1500 p.s.i. and atspeeds of 5.1 cu. in./sec. The pump according to the invention is thusable to move efficiently high volumes of liquid at hydraulic backpressures at high speeds.

Reasonable variation and modification are possible within the scope ofthe foregoing disclosure, the drawings, and the appended claims withoutdeparting from the spirit of the invention.

The embodiments of the invention in which an exclusive property orprivilege is claimed are defined as follows:

1. A high speed, high volume hydraulic pump formed from a plurality ofplate members including a base member, a cylinder plate member, and asuction plate member, said cylinder plate member being fixed betweensaid base member and said suction plate member; a pump cavity formed insaid cylinder plate member; intermeshing gear means within said pumpcavity having close tolerances between the walls of said pump cavity andouter portions of said gear means; a drive shaft extending through saidbase and rigidly fixed on one of said intermeshing gear means; an outletconduit means in said suction plate member communicating with said pumpcavity at an intake side of the point of meshing of said gear means; anoutlet conduit communicating with said pump cavity at an opposite pointof meshing of said gear means, so that liquid in said inlet conduitmeans can be pumped to said outlet conduit means as said gear meansrotates within said pump cavity, the improvement which comprises: axialaligning pins in said base member extending through said cylinder platemember and into at least a portion of said suction plate member, therebyensuring precise alignment of said base member, said cylinder platemember, and said suction plate member, whereby close tolerances can bemaintained between the walls of said pump cavity and the outer portionsof said gear means, and O-ring seal means between each of said platemembers to seal off said pump cavity to prevent leakage of fluid fromsaid pump cavity.

2. The high speed, high volume hydraulic pump of claim 1 furthercomprising: a recycle conduit in said base member communicating at oneend with said one side of the point of interengagement of said gearmeans, and at the other end with said opposite point of engagement ofsaid gear means; and biased check valve means in said recycle conduit topermit fluid to flow from said discharge side to said intake side whenthe pressure at said discharge side exceeds that of said intake side bya predetermined value.

3. The high speed, high volume hydraulic pump of claim 1, wherein saidgear means have a thickness substantially the same as said cylinderplate, and further comprising a wear plate member between said cylinderplate and said base member, said wear plate forming a bearing surfacefor said gear means, whereby said wear plate member can be replaced ormachined as said bearing surface wears to maintain close toleranceswithin said pump cavity.

4. A high 'speed, high volume hydraulic pump according to claim 1,wherein each of said gear means has eleven.

equally spaced teeth, each tooth being generally frustroconicallyshaped, each tooth being spaced at the base from an adjacent tooth adistance substantially equal to the width of each tooth at the peak.

5. A high speed, high volume hydraulic pump according to claim 4 whereinthe sides of each tooth are bowed outwardly toward adjacent teeth.

6. A high speed, high volume hydraulic pump according to claim 1,wherein each of said gear means has a plurality of equally spaced teeth,each tooth being generally frustro-conically shaped, each tooth beingspaced at the base from an adjacent tooth a distance substantially equalto the width of each tooth at the peak, and the sides of each tooth arebowed outwardly toward adjacent teeth.

7. A high speed, high volume hydraulic pump formed from a plurality ofplate members including a base member, a cylinder plate member, and asuction plate member, said cylinder plate member being fixed betweensaid base member and said suction plate member; a pump cavity formed insaid cylinder plate member; intermeshing gear means within said pumpcavity having close tolerances between the walls of said pump cavity andouter :portions of said gear means; a drive shaft extending through saidbase and engaging one of the said intermeshing gear means; an inletconduit means in said suction plate member communicating with said pumpcavity at an intake side of a point of meshing of said gear means; anoutlet conduit communicating with said pump cavity at an opposite pointof meshing of said gear means, so that liquid in said inlet conduitmeans can be pumped to said outlet conduit means as said gear meansrotate within said pump cavity; the improvement which comprises:

a recycle conduit in said base member communicating at one end with saidone side of a point of meshing of said gear means, and at the other endwith said opposite point of meshing of said gear means; and

biased check valve means in said recycle conduit to permit fluid to flowfrom said discharge side to said intake side when the pressure at saiddischarge side exceeds that of said intake side by a predeterminedvalue.

8. A high speed, high volume hydraulic pump formed from a plurality ofplate members, said pump comprising:

a base member, a wear plate member, a cylinder plate member, and asuction plate member, said wear plate member being in face to facecontact with said base member, said cylinder plate member being fixedbetween said wear plate member and said suction plate member;

a pump cavity formed in said cylinder plate member;

intermeshing gear means within said pump cavity having close tolerancesbetween the walls of said pump cavity and outer portions of said gearmeans, said gear means including a plurality of equally spaced teeth,each tooth being generally frustro-conically shaped, with the sidesthereof bowed outwardly toward adjacent teeth, each tooth being spacedat the base from an adjacent tooth a distance substantially equal to thewidth of each tooth at the peak;

a drive shaft extending through said base and rigidly engaging one ofthe said intermeshing gear means;

an inlet conduit means in said suction plate member communicating withsaid pump cavity at an intake side of a point of meshing of said gearmeans;

an outlet conduit communicating with said pump cavity at an oppositepoint of meshing of said gear means, so that liquid in said inletconduit means Will be pumped to said outlet conduit means as said gearmeans rotates within said pump cavity;

axial aligning pins in said base member extending through said wearplate member and said cylinder plate member and into at least a portionof said suction plate member thereby ensuring precise alignment of saidbase member, said wear plate member,

said cylinder plate member and said suction plate member, whereby closetolerances can be maintained between said walls of said pump cavity andthe outer portions of said gear means;

a recycle conduit in said base member communicating at one end with saidone side of a point of meshing of said gear means, and at the other endwith said opposite point of meshing of said gear means;

biased check valve means in said recycle conduit to permit fluid to flowfrom said discharge side to said intake side when the pressure at thedischarge side exceeds that of said intake side by a predeterminedvalue;

said gear means having a thickness substantially the same as that ofsaid cylinder plates; and

O-ring seal means between each of said plate members to seal off saidpump cavity to prevent external leakage of fluid from said pump cavity.

9. A high speed, high volume hydraulic pump according to claim 8 furthercomprising indented slots formed in said wear plate at either side ofmeshing of said gear means to permit pressure relief at those points.

References Cited UNITED STATES PATENTS 1,912,737 6/1933 Svenson103l26(BY) 2,395,824 3/1946 Herman l03l26(M) 2,842,006 7/1958 Edman103126(H) 3,096,719 7/1963 McAlvay 103-126(H) 3,128,710 4/1964 Blomgrenet a1. 103-126(BY) 3,170,408 2/1965 Hill et a1 l03l26(BY) MARK NEWMAN,Primary Examiner W. J. GOODLlN, Assistant Examiner

